1/* 2 * Copyright (c) 2009 Felix Obenhuber 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 3. The name of the author may not be used to endorse or promote 15 * products derived from this software without specific prior written 16 * permission. 17 * 18 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 19 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 20 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 21 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 22 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 23 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 24 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 25 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 26 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 27 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 28 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 29 * 30 * SocketCan sniffing API implementation for Linux platform 31 * By Felix Obenhuber <felix@obenhuber.de> 32 * 33 */ 34 35#ifdef HAVE_CONFIG_H 36#include "config.h" 37#endif 38 39#include "pcap-int.h" 40#include "pcap-can-linux.h" 41 42#ifdef NEED_STRERROR_H 43#include "strerror.h" 44#endif 45 46#include <errno.h> 47#include <stdlib.h> 48#include <unistd.h> 49#include <fcntl.h> 50#include <string.h> 51#include <sys/ioctl.h> 52#include <sys/socket.h> 53#include <net/if.h> 54#include <arpa/inet.h> 55 56#include <linux/can.h> 57#include <linux/can/raw.h> 58 59/* not yet defined anywhere */ 60#ifndef PF_CAN 61#define PF_CAN 29 62#endif 63#ifndef AF_CAN 64#define AF_CAN PF_CAN 65#endif 66 67/* forward declaration */ 68static int can_activate(pcap_t *); 69static int can_read_linux(pcap_t *, int , pcap_handler , u_char *); 70static int can_inject_linux(pcap_t *, const void *, size_t); 71static int can_setfilter_linux(pcap_t *, struct bpf_program *); 72static int can_setdirection_linux(pcap_t *, pcap_direction_t); 73static int can_stats_linux(pcap_t *, struct pcap_stat *); 74 75pcap_t * 76can_create(const char *device, char *ebuf) 77{ 78 pcap_t* p; 79 80 p = pcap_create_common(device, ebuf); 81 if (p == NULL) 82 return (NULL); 83 84 p->activate_op = can_activate; 85 return (p); 86} 87 88 89static int 90can_activate(pcap_t* handle) 91{ 92 struct sockaddr_can addr; 93 struct ifreq ifr; 94 95 /* Initialize some components of the pcap structure. */ 96 handle->bufsize = 24; 97 handle->offset = 8; 98 handle->linktype = DLT_CAN_SOCKETCAN; 99 handle->read_op = can_read_linux; 100 handle->inject_op = can_inject_linux; 101 handle->setfilter_op = can_setfilter_linux; 102 handle->setdirection_op = can_setdirection_linux; 103 handle->set_datalink_op = NULL; 104 handle->getnonblock_op = pcap_getnonblock_fd; 105 handle->setnonblock_op = pcap_setnonblock_fd; 106 handle->stats_op = can_stats_linux; 107 108 /* Create socket */ 109 handle->fd = socket(PF_CAN, SOCK_RAW, CAN_RAW); 110 if (handle->fd < 0) 111 { 112 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "Can't create raw socket %d:%s", 113 errno, strerror(errno)); 114 return PCAP_ERROR; 115 } 116 117 /* get interface index */ 118 memset(&ifr, 0, sizeof(ifr)); 119 strncpy(ifr.ifr_name, handle->opt.source, sizeof(ifr.ifr_name)); 120 if (ioctl(handle->fd, SIOCGIFINDEX, &ifr) < 0) 121 { 122 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, 123 "Unable to get interface index: %s", 124 pcap_strerror(errno)); 125 pcap_cleanup_live_common(handle); 126 return PCAP_ERROR; 127 } 128 handle->md.ifindex = ifr.ifr_ifindex; 129 130 /* allocate butter */ 131 handle->buffer = malloc(handle->bufsize); 132 if (!handle->buffer) 133 { 134 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "Can't allocate dump buffer: %s", 135 pcap_strerror(errno)); 136 pcap_cleanup_live_common(handle); 137 return PCAP_ERROR; 138 } 139 140 /* Bind to the socket */ 141 addr.can_family = AF_CAN; 142 addr.can_ifindex = handle->md.ifindex; 143 if( bind( handle->fd, (struct sockaddr*)&addr, sizeof(addr) ) < 0 ) 144 { 145 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "Can't attach to device %d %d:%s", 146 handle->md.ifindex, errno, strerror(errno)); 147 pcap_cleanup_live_common(handle); 148 return PCAP_ERROR; 149 } 150 151 if (handle->opt.rfmon) 152 { 153 /* Monitor mode doesn't apply to CAN devices. */ 154 pcap_cleanup_live_common(handle); 155 return PCAP_ERROR; 156 } 157 158 handle->selectable_fd = handle->fd; 159 return 0; 160 161} 162 163 164static int 165can_read_linux(pcap_t *handle, int max_packets, pcap_handler callback, u_char *user) 166{ 167 struct msghdr msg; 168 struct pcap_pkthdr pkth; 169 struct iovec iv; 170 struct can_frame* cf; 171 172 iv.iov_base = &handle->buffer[handle->offset]; 173 iv.iov_len = handle->snapshot; 174 175 memset(&msg, 0, sizeof(msg)); 176 msg.msg_iov = &iv; 177 msg.msg_iovlen = 1; 178 msg.msg_control = handle->buffer; 179 msg.msg_controllen = handle->offset; 180 181 do 182 { 183 pkth.caplen = recvmsg(handle->fd, &msg, 0); 184 if (handle->break_loop) 185 { 186 handle->break_loop = 0; 187 return -2; 188 } 189 } while ((pkth.caplen == -1) && (errno == EINTR)); 190 191 if (pkth.caplen < 0) 192 { 193 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "Can't receive packet %d:%s", 194 errno, strerror(errno)); 195 return -1; 196 } 197 198 /* adjust capture len according to frame len */ 199 cf = (struct can_frame*)&handle->buffer[8]; 200 pkth.caplen -= 8 - cf->can_dlc; 201 pkth.len = pkth.caplen; 202 203 cf->can_id = htonl( cf->can_id ); 204 205 if( -1 == gettimeofday(&pkth.ts, NULL) ) 206 { 207 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "Can't get time of day %d:%s", 208 errno, strerror(errno)); 209 return -1; 210 } 211 212 callback(user, &pkth, &handle->buffer[8]); 213 214 return 1; 215} 216 217 218static int 219can_inject_linux(pcap_t *handle, const void *buf, size_t size) 220{ 221 /* not yet implemented */ 222 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "inject not supported on " 223 "can devices"); 224 return (-1); 225} 226 227 228static int 229can_stats_linux(pcap_t *handle, struct pcap_stat *stats) 230{ 231 /* not yet implemented */ 232 stats->ps_recv = 0; /* number of packets received */ 233 stats->ps_drop = 0; /* number of packets dropped */ 234 stats->ps_ifdrop = 0; /* drops by interface -- only supported on some platforms */ 235 return 0; 236} 237 238 239static int 240can_setfilter_linux(pcap_t *p, struct bpf_program *fp) 241{ 242 /* not yet implemented */ 243 return 0; 244} 245 246 247static int 248can_setdirection_linux(pcap_t *p, pcap_direction_t d) 249{ 250 /* no support for PCAP_D_OUT */ 251 if (d == PCAP_D_OUT) 252 { 253 snprintf(p->errbuf, sizeof(p->errbuf), 254 "Setting direction to PCAP_D_OUT is not supported on can"); 255 return -1; 256 } 257 258 p->direction = d; 259 260 return 0; 261} 262 263 264/* eof */ 265